The present invention relates to a bearing for a textile machine spinning rotor having a rotor shaft driven by a tangential belt.
In conventional open-end spinning devices the spinning rotors of the individual spining stations are normally supported in the nip of one pair of bearing disks as shown in German Patent 33 46 843 A1, or of two pairs of bearing disks, and are driven by means of a tangential belt which extends over a plurality of spinning stations adjoining each other (German patent 37 30 705 A1). It has been found that irregular oscillations or tension fluctuations occur in the tangential belt and that these are transmitted to the rotor shaft in such manner that the rotor shaft is pushed with varying force into the nip constituted by the bearing disks. Due to the varying tension of the tangential belts, the rotor shaft intermittently comes loose from the circumferential surfaces of the bearing disks forming the nip, and are then again pressed back by the tangential belt on the circumferential surfaces of the bearing disks. As a result of this the bearing disks and the rotor shaft are subjected to increased wear. In order to achieve an axial thrust on the spinning rotor, the axes of the bearing disks are placed in most spinning rotor bearings at only a very slight angle to each other, so that the axes of the bearing disks are not strictly on one and the same plane. This slight geometric deviation shall however not be taken into consideration hereinafter since it is of no consequence for the present invention.
It is therefore a principal object of the present invention to reduce the possibility of movement of the spinning rotor in the nip to such an extent that no increased mechanical stress, in particular impact stress, is incurred by the interacting parts of the bearing, in particular of the bearing disks and the rotor shaft, in order to extend the life of these parts. Additional objects and advantages of the invention will be set forth in part in the following description or may be obvious from the description, or may be learned through practice of the invention.
The above-mentioned object is attained through having the axis of a bearing disk rotating into the nip formed by two bearing disks at a specified distance from a plane which passes through the rotor shafts of the spinning rotors of adjoining open-end spinning devices, where the specified distance is less than the distance between the axis of the other disk rotating out of the nip and the plane. The inclination of the plane in which the axes of the bearing disks are located relative to the plane which runs through the axes of the spinning rotors of adjoining spinning stations causes the nip or its central axis not to be at a right angle to the plane going through the axes of the spinning rotors but, as seen in the running direction of the tangential belt, is at an acute angle to these axes.
The inclination of the plane means that the circumferential surfaces of the bearing disk which leads the tangential belt, i.e. which is located after the rotor shaft as seen in the running direction of the tangential belt presents a steeper nip flank to the rotor shaft for an otherwise identical bearing disk diameter. This acts in opposition to a rising tendency of the rotor shaft on the circumferential surface of this bearing disk which rotates into the nip. Even though the tangential belt imparts a motion component to the rotor shaft which is opposite to the rotational direction of this bearing disk which rotates into the nip, no danger exists that the rotor shaft may leave the position in which it is in contact with the bearing disk(s) rotating into the nip as well as with the bearing disk(s) rotating out of the nip, so that the running of the spinning rotor is very quiet. This has a positive effect not only on the circumferential surfaces of the bearing disks of the rotor shaft but also causes an evening-out of the yarn produced in the spinning rotor.
An embodiment of the invention can further counteract tension fluctuations in the tangential belts driving the rotor shafts, and thereby to further reduce the danger that the rotor shafts may run erratically in their nips. The axes of the bearing disks may be supported in a bearing support capable of swiveling at its one end that is subjected to the pressure of an elastic element pressing it in the direction of the tangential belt.
It has proven to be advantageous, for bearing disks of normally used diameters, if the plane going through the axes of the bearings disks forms a specified angle between 5xc2x0 to 15xc2x0 with the plane going through the axes of the spinning rotors of adjoining spinning stations.
The invention produces quiet running of the spinning rotor since it reduces the possibility for the rotor shaft to move radially in the nip. This fact also leads to a reduction of mechanical stress to the bearing disks and the rotor shaft and thereby to an extension of the life of the interacting rotating parts of the bearing. The quiet rotor rotation obtained by means of the device according to the invention furthermore results in an evening-out of the yarn produced in the spinning rotor.
An example of an embodiment of the device according to the invention is explained in further detail below through drawings.